Hydraulically actuated linkages



July 23, 1957 H. G. CONWAY HYDRAULICALLY ACTUATED LINKAGES 2 Sheets--Shee'l'l lv Filed Oct. 20, 1953 bfi-Jh HIM@ www

H. G. CONWAY HYDRAULICALLY ACTUATED LINKAGES July 2,3, 1957 2 sheets-sheer` 2 Filed Oct. 20, 1.953

IN vENToR afb United States Patent 4ik@ 2,799,992 HYDRAULICALLY AcrUArEn LINKAGES- nirghorahamconway, Gamestar/,England assigno'rfto Brtish Messier 'Limits/ed, Gloucester, Englandya British company Application-*Gerbrand l1953,'serial-N0. 387,272 y Claims priority, application Great Britain oefober 29, 1952 s claims. (C1, 60-51) This invention comprises improvements in or relating tohydraulic actuators;

It is an object of the invention to provide an'actuator which is capable of exerting force on more than one operated elements at one time, by means of a single jack element in which the various forcesa-nd'reactions' areas far as possible borne by self-contained partsof the actuator. It is a further object of -the inventionfto provide an actuator in which lateral stresses on the jackV rod are avoidedwithout the ern'ployrr'rentl ofv any cross head and slide mechanisms, because such mechanisms are liable to be weighty and to introduce undue frictional losses.

According to the present invention alhydrali'c'actuator comprises a base, a jack secured thereto, bracket means supported from the base for carrying a parallel motion, In'eansY connecting the moving element of the' jack to the part ofthe parallel motion which executes astraight line movement, and transmitting rn'eansfor the force'to be exerted by the actuator, which transmitting means'V are operated by themembers of the parallel motion. By having the jack connected to the parallel motion in the manner described lateral forces on the jack are obviated Without usingguides, and by having the parallel motion mounted on a bracket which is supported bythe base the lateral land reaction forces arev self-contained. If an actuator is mounted in an aircraft this is important because it means that a minimum of structural reinforcement is required in the aircraft structureitself.

In the specific form-of actuator hereinafter described, the actuator is used for exerting a plurality of forces, each exerted through a diierent part of the parallel motion, and thus the motion serves also as a distributing mechanism for the forces.

Preferably, the parallel motion is a Watt motionan'd the transmitting members for the forcesfare connected to levers which'form extensions of theswinging links of the motion. t

The bracket means which are' supported by.y the base and which carry the parallel motion may be formed-by utilising hydraulic accumulators, required for' actuating the jack, as part ofthe bracket structurei In a preferred construction, the base carries two parallel cylinders to constitute accumulator casings, which cylinders are spaced apart from one another and the jack cylindert is mounted onl the base between them. The ends of the accumulator cylinder carry extensions which support pivots for swinging llinks lof a vWatt type parallel motion, and the two extensions on the accumulatorY cylinders are united by a tie-bar so as to render the structure more rigid.

The following is a description by way of example of one construction of'hydraulic actuator in accordance with the invention:

In the accompanying drawing,

Figure l is a plan of the actuator,

Figure 2 is an end view of the same as located in an aeroplane wing-spar, and l A p Figure 3 isa planot a portion of a wing showing the actuator located therein and connected to two-leading edge aps.

2,799,992 Patented 'July 23, 1957 The actuator '1'11is intended to be locatedin a wing 12 of an airc'ra'ft'nearV t-lte centre of the leading' edge to operate leading edge aps 13, 14. The flaps 13, 14 extend along andform part of the leading edge andthe actuator 11 is situated-atthe'junction yofthe two aps so as to operate a link-Work bywhicli the aps are extended or retracted, The detail of the linkwork forms no partof the present invention, and isv notshown `in the drawing. It issuicien't to explain that the actuator operates two push-rods' 15, 16,- which operate one on each lof the adjacentve'nds' of; the tiaps 13 and 14, and that by means of linkwork, which extends` alon'gthe wing within the aps, the outer ends 113, 114' of the aps are caused to move forward or backward parallel to the inner ends 115, 116A accordingto" the direction in which force is vexerted'on ther'ods 15l and 16;

In'the wingbeliin'd theaps is'anupright'webV 17, forming partfof the wingstructure, which extends parallel Withfthe aps,-and'irito this web there is tted a large base block 18- of forged` light-metal alloy. The upper ancl-Y lower surfaces of the wing structure are indicated in Figure 2 lat'19 'and 20 respectively.

The base block is machined to receive the ends of two accumulator cylinders? 21, 22, which extend from the* base 'block parallel with one another into the hollow wing'behindl--the vertical web 17, in a more or less hori- Zontal direction. Between the accumulator cylinders a jackv cylinder`2`3 is let into' the base block and extends paralleliWi-ththem, in'rthe same plane. As can be seen in Figure l, thecylinder 21- carries a ange 24, on which bears'a sleeveZS, screw'ed'into'the bracket 18, and surrounding the" cylinderZ'l behind the ange 24. In this Waythecylinderis held-firmly in-theblock. The cylinder 22 and jack 23`are similarly secured.4

The rear (outer) ends ofthe accumulator cylinders 21, 22 are closed by caps 26, 27, united to bracket elements '28, 29 which form extensions of the cylinders and the ends'of-whichare unitedtogether by a cross bar'30.

Each of -thel `bracketelements-28, `29 `contains a pivot (31, 32), fora swinging lever (33, 34), and the two swinging level-'sare united-byalink 35 so as to form a Watt type parallel Ymotion, thefcentreof the link moving in a' straight lin'e.` p

The' jack-cylinde23 l'contains a pistonand ram 36, and the endof the ratr'i'36 extends through a stuing box toward-the'l-ink 35 of. the parallel motion. The end of the ramgisflinked to the 'straight line point of the parallel motionfby two link members v37, one'infront and one-behind thellink 35er? thef'parallel motion. The link of the parallel motionitself is' forked to receivethe ends of'the two 'levers`33, 34,' which are pivoted on't'nebracket4 extensions'28, `29 from' thefaccumulator cylinders.

Thefswinging levers 33, 34 project beyond their pivots on:ea'ch=side`of -the extensions` and are connected by pin joints to theactuatorrodsV 15, 16 already referred to, which extend'from-them parallel withtheaccumulator cylinders inv a forward direction,` passing throughv the vertical web 17 iu the wing to which the base 18ct the actuator` isf attached and being connected in front of this web Vtothe linirwork'whichoperates the flaps 13,714. On the vfront fa'c'e'of the base 18,that istosay the opposite face from that-on whichvthe-accumulaors and jack cylinder project, there is secureda valve box 40, which contains passages forA the-flow of the hydraulic operatingifluid andvalves to determine the operation-of the accumulators 21, 22, and the jack23. The internal construction-of the valve box forms no part of the present invention. The outerends ofthe accumulatore 21, 22, are connected by-air-pipes v41, 42 to inilation connections 43, A44; secured -to the block IS. The jack 23has'a hy- -draulicconnection 45,` which extends from'the block 18 to the endof'the'ja'ck nearest tothe linkwork, andthe valves in the valve-box 40 can direct either hydraulic pressure or accumulator pressure to either end of the jack 23, which is double-acting. 46 is a connection to tank, and the supply connections are made to entrance ports 47, 48 in the block V11. rInternal passages, are drilled in the block 18 ybetween the various parts as required. c g

It will be seen that in a construction .ofA hydraulic actuator as just described, the two actuating rodsY 15, 16,

- are both operated simultaneously by asingle jack `element A3,6, and that with exception yof the forces exerted by these rods, all the forces and reactions arey self-contained within the actuator. Therefore, theV minimum of stress is exerted on the wing structureitself.V The accumulator cylinders 21, 22Y which take the tensional reaction `stress when Vthe jack is extended, .ware in line with the reaction which they are resisting, andl as the longitudinal stress in the accumulator cylinders due to the internal pressure thereof, is only one half the circumferential stress,they have an adequate strength to withstand this reaction, and the weight of separate bracket means is saved. The straight line movement of the parallel motion needV not be more than a few thousandths of an inch 'out of true from the geometrically straight line, and therefore, the link members which connect this point tothe jack ram do not exert any appreciable lateral force on the .ram and the Vweight and frictioniof a sliding guide and cross head, which would Votherwise, he required, is obviated.

Moreover, if for any reason it is necessary Vtoarrange for one ofV the ap actuating rods Y15 or 1,6, to have a greater movement than the other, this can be easily arranged by varying the proportions of the linksrof Vthe Watt motion, without necessitating yalteration in the de- Ysign of'other parts of the unit. Y

ln fact it will be seen that in the drawing the link 33 is longer from'its pivotgpont on the bracket 2S to its pivot point on the rod 16, than the corresponding portion Y of the link 34, :and the rod 16 will therefore, have a greater movement than the rod, 15.

I claim: l. A hydraulic actuator, especially for aircraft, to

Y exert force on two independently-,movable,operated elements at one time, comprising a base, a duid-operated jack having a fixed element secured to the base and a moving element to execute a straightrline motion with. respect thereto, bracket means supported from the base on either side of the jack, two swinging links pivoted on the bracket means at equal distances from the vjacky axis on opposite sides thereof and having portions of equal length extending inwardly toward the jack Yaxis,a connecting link having one of its ends pivoted to the inner end of one of the swinging links and the other end pivoted to the inner end ofthe other swinging link, which Connecting link is itself pivotally mounted, at a point intermediate said end pivots, on the moving element of the jack, all

the aforementioned pivots havingl theirV axes parallel to one another and at right angles to the line of motion of said moving element, andthe connecting link being oblique to said line, and members for moving the two operated elements pivotally connected to the swinging links at points spaced from pivots of the links on the bracket means.

2. A hydraulic actuator, especially for aircraft, to exert force on two independently-movable operated elements at one time, comprising a base, a huid-operated jack having a iixed element secured to the base and a moving element to execute a straight line motion with respect thereto, bracket means supported from the base on either side of the jack, two swinging links pivoted on the bracket means at equal distances from the jack axis on opposite sides thereof, said swinging links having portionsof equal length extending inwardly toward the jack and Vextensions outwardly of their pivots on the bracket means, a connecting link Ihaving one of its ends pivoted to the inner end of one of the swinging links and the other end being oblique to said line,-and rod members for moving the two operated elements disposed outside the bracket means on both sides of the actuator and substantially parallel to the line of motion of the moving jack element, the ends of said rod members being pivoted to the outer ends of the swinging link extensions and the rod members extending from the pivots toward the base of the actuator.

3. A hydraulic actuator as claimed in claim 1, wherein the bracket means whichV are supported fromthe base, and on which are pivoted the swinging links, are formed by utilizing hydraulic accumulators, required for actuating the jack, as part of the bracket structure.

4. A hydraulic actuator as claimed in claim l, wherein the base carries two parallel cylinders constituting accumulator casings, which cylinders are spaced apart from Yone another, and the jack cylinder is mounted on the base between them. Y Y Y 5. A hydraulic actuator as claimed Vin claim V4, wherein extensions on the ends of the accumulator cylinders remote from the base support the pivotsfor the swinging links, and a tie bar unites the ends of the two extensions on the accumulator cylinders so as to render the structure more rigid. n

6. A hydraulic actuator as claimed in claim l, wherein the moving element of the jack has a point of articulation between the fixed element of the jack andthe pivot on said movingr element for the connecting link. f

7. A hydraulic actuator, especially for aircraft, to exert force on two independently-movable operated elements at one time, comprising abase, a fluid-operated jack having `a fixed element secured to the base and a moving element to execute a straight line motion with respect thereto, bracket means supported from the base on either side of the jack, twoV swinging links pivoted on the bracket vmeans at equal distances from Athe jack axis on opposite v sides thereof,.said swinging links having portions of equal length extending inwardly toward the jack axis and extensions outwardly of their pivots on the bracket means, a connecting link having one of its ends pivoted to the inner end of one of the swinging links and the other end pivoted to theinner end of the other swinging link, which connecting link is itself pivotally mounted,` at a point intermediate said end. pivots, on the moving element ofV the jack, all the aforementioned pivots having their axes parallel to one another and at right angles to the line'of motion of said moving element, and the connecting link being oblique to said line, and actuating members connected to the two operated elements disposed outside the bracket means on both sides of the actuator and pivotally connected to said extensions. Y.

8. A hydraulic actuator as claimed in claim 7, wherein on one swinging link extension the distance between the pivot of the link on the bracket means and the pivotal connection of one actuating member is greater than the equivalent distance on the other swinging link extension,

whereby one operated element moves by greater amounts than the other. Y

References Cited in the file of Athispatent UNITED STATES PATENTS Horne Mar. 2, 192i) Greer et al. May 6, 1952 

